An optical fiber scanner, which is a device for obtaining an external image using an optical fiber, may easily approach a photographing target and be easily manipulated, such that it is used in various industrial fields. Particularly, miniaturization of a device is easy, such that utilization of the optical fiber scanner as a medical scanner and a scanner of an endoscope is high.
FIG. 1 is a schematic view showing an optical fiber scanner according to the related art.
As shown in FIG. 1, the optical fiber scanner according to the related art is configured to include a driving means 20 disposed at one end of an optical fiber 10 and vibrating the optical fiber 10, a lens 30 disposed at the other end of the optical fiber and focusing light, and a housing 40 in which the optical fiber 10, the driving means 20, and the lens 30 are disposed. Here, as the driving means 20, a micro motor, a piezoelectric, a complementary metal oxide semiconductor-micro electro mechanical systems (CMOS-MEMS) mirror, or an MEMS mirror may be used.
In the related art, in the case in which the driving means is configured at a micro-miniature size (radius of 2 mm or less), since driving displacement of the driving means is fine, scanning displacement of the optical fiber has been limited to a predetermined range. Therefore, a method of extending the scanning displacement of the optical fiber by driving the driving means at a resonance frequency of the optical fiber has been used. Here, in the case in which the driving means is driven at the resonance frequency of the optical fiber, the scanning displacement of the optical fiber is extended by a resonance phenomenon of the optical fiber.
Here, in order for the optical fiber to have a scanning speed (resonance frequency) of 100 Hz or less, the optical fiber should have a very long length of 30 mm or more. Therefore, a method of installing a separate mass body at an end portion of the optical fiber to increase effective mass of the optical fiber has been suggested.
However, in the related art, as shown in FIG. 2, since both of the optical fiber and the mass body are circularly formed so as to be symmetrical in X and Y directions, a resonance frequency of the optical fiber in the X direction and a resonance frequency of the optical fiber in the Y direction are the same as each other, such that only circular scanning is possible in a two-dimensional driving pattern of the optical fiber. As a result, there is a problem that only spiral scanning using amplitude modulation is possible in the optical fiber.
In addition, there is a scanner using a driver using a piezoelectric (PZT) element. However, since a very high cost is required for manufacturing a PZT tube, it is difficult to commercialize the scanner using the driver using the PZT element.
Therefore, development of an optical fiber scanner for solving the above-mentioned problems has been demanded.